1. Field of the Invention
The present invention relates to a document management apparatus, a document management system, a document management client apparatus, and a document management method.
2. Discussion of the Background
Today, electronic documents are widely used and are generalized. Concurrently with such wide use and generalization of electronic documents, electronic document management systems have drawn attention, and various products and standards for document management systems have been proposed. Such document management systems enable integrally managing, as one document, not only a document file itself, but also a plurality of versions, thumbnails and retrieval indexes thereof.
As a standard of electronic document management systems, the specification of the Document Management Alliance (DMA) is known. The primary object of the DMA is to develop an industry standard specification for document management systems. The DMA provides an API (Application Programming Interface) and a document model for unification of all document management systems. The DMA defines a document not as a simple file but as a more comprehensive model. The details of the DMA specification can be found at in DMA Technical Committee. DMA 1.0 Specification. AIIM International: Silver Spring, Md., 1998 and are known to one of ordinary skill in the art.
FIG. 1 is a block diagram illustrating an outline of the document structure of a document according to the document object model of the DMA. As illustrated in FIG. 1, according to the document object model of the DMA, one document 100 has a tree-structure constituted of a plurality of hierarchies. The root node 100 in the hierarchical tree-structure of a document corresponds to one document object, which is, in the example of FIG. 1, a report. The document object has properties, such as a title, an author, etc.
One document object is constituted of a plurality of versions 112, 114. Each version object 112, 114 has properties, e.g., a version number, a creation date, etc. In the example of FIG. 1, two versions exist, version 1.0 112 and version 2.0 114.
One version object is constituted of a plurality of renditions 116, 118. A rendition represents a rendering form of a document. For example, in a case of a document created by a word processor, in addition to a document file created by the word processor, a JPEG format image file for a thumbnail, a PDF format file, a text format file, etc. may be conceivable. Each document object includes a plurality of renditions as described above. However, always a primary rendition 116 exists. The primary rendition 116 is the one created as the original format of each document, and is the subject file for editing.
One rendition is constituted of a plurality of content elements 120, 124. A document is not necessarily constituted of one document file. For example, when a document includes a document file created by a word processor and a spreadsheet file created by a spreadsheet, respective files constitute content elements of the document, according to the DMA document object model.
FIG. 2 is a diagram illustrating a communication sequence between a client and a document management apparatus that uses the DMA specification (i.e., a DMA-compliant document management apparatus) when the client accesses the document management apparatus to call a content element of a desired document. FIG. 2 illustrates a case in which, for the document illustrated in FIG. 1, the top content element of the thumbnail rendition is called by the client.
First, the client calls the document object of the document (which is a report) using a document object ID. The document management apparatus connects the client to the document object of the report, and the document object of the report is returned to the client. Next, the client calls the version 2.0, the document management apparatus connects the client to the version 2.0, and the version 2.0 is returned to the client. Further, the client calls the thumbnail rendition, the document management apparatus connects the client to the thumbnail rendition, and the thumbnail rendition is returned to the client. Finally, the client calls the top content element at the lower level of the thumbnail rendition, the document management apparatus connects the client to the top content element, and the top content element is returned to the client.
In the currently available DMA API according to the DMA specification, each time a user accesses a document that uses the DMA document object model, the process described above with reference to FIG. 2 must be performed. This process is relatively complicated. This causes an application program for accessing the document that uses the DMA document object model to be relatively complicated.
Further, some document management systems do not support version and rendition information. In this case, the DMA API cannot be used.
Furthermore, according to the DMA specification, version, rendition and content element information must be specified. However, some clients might use a simpler document model. For example, a client might not manage version information in a system on the client side. In such a case, when the user accesses a document that uses the DMA specification, the client cannot designate a version of the document, so that the document cannot be accessed.